Coronary Artery Calcium for Personalized Allocation of Aspirin in Primary Prevention of Cardiovascular Disease in 2019

Abstract

Background: Recent American College of Cardiology/American Heart Association Primary Prevention Guidelines recommended considering low-dose aspirin therapy only among adults 40 to 70 years of age who are at higher atherosclerotic cardiovascular disease (ASCVD) risk but not at high risk of bleeding. However, it remains unclear how these patients are best identified. The present study aimed to assess the value of coronary artery calcium (CAC) for guiding aspirin allocation for primary prevention by using 2019 aspirin meta-analysis data on cardiovascular disease relative risk reduction and bleeding risk. Methods: The study included 6470 participants from the MESA Study (Multi-Ethnic Study of Atherosclerosis). ASCVD risk was estimated using the pooled cohort equations, and 3 strata were defined: <5%, 5% to 20%, and >20%. All participants underwent CAC scoring at baseline, and CAC scores were stratified as =0, 1 to 99, ≥100, and ≥400. A 12% relative risk reduction in cardiovascular disease events was used for the 5-year number needed to treat (NNT 5 ) calculations, and a 42% relative risk increase in major bleeding events was used for the 5-year number needed to harm (NNH 5 ) estimations. Results: Only 5% of MESA participants would qualify for aspirin consideration for primary prevention according to the American College of Cardiology/American Heart Association guidelines and using >20% estimated ASCVD risk to define higher risk. Benefit/harm calculations were restricted to aspirin-naive participants <70 years of age not at high risk of bleeding (n=3540). The overall NNT 5 with aspirin to prevent 1 cardiovascular disease event was 476 and the NNH 5 was 355. The NNT 5 was also greater than or similar to the NNH 5 among estimated ASCVD risk strata. Conversely, CAC≥100 and CAC≥400 identified subgroups in which NNT 5 was lower than NNH 5 . This was true both overall (for CAC≥100, NNT 5 =140 versus NNH 5 =518) and within ASCVD risk strata. Also, CAC=0 identified subgroups in which the NNT 5 was much higher than the NNH 5 (overall, NNT 5 =1190 versus NNH 5 =567). Conclusions: CAC may be superior to the pooled cohort equations to inform the allocation of aspirin in primary prevention. Implementation of current 2019 American College of Cardiology/American Heart Association guideline recommendations together with the use of CAC for further risk assessment may result in a more personalized, safer allocation of aspirin in primary prevention. Confirmation of these findings in experimental settings is needed.

Highlights of the 15th annual scientific meeting of the Society of Cardiovascular Computed Tomography

“… 14 He also highlighted the beneficial impact CACS might have on selecting those who have most to gain from the use of aspirin as a primary preventative agent. 15 These findings were further complemented by an excellent presentation from Dr. Kelly Han in the Young Investigator Award session on the clinical significance of subtle coronary artery calcification. This is calcification that is < 130HU, or <1mm3.…”

Coronary CT Angiography Guided Medical Therapy in Subclinical Atherosclerosis

“…This analysis had recently been repeated by the MESA group in response to the adoption of the PCE for clinical risk assessment of atherosclerotic cardiovascular disease (ASCVD) [46]. 3540 patients were included in the analysis, patients were excluded if they were >70 years old, had a high risk of bleeding or were on aspirin at baseline.…”

“…Patients with a coronary calcium score ≥100 had net benefit of aspirin independent of the calculated ASCVD risk. In those patients with a CAC of zero there was a net harm of bleeding across the ASCVD strata [46]. CAC imaging therefore can be useful in refining the risk/benefit for primary prevention with aspirin.…”

“…The ACC/AHA primary prevention guideline recommends low-dose aspirin use (75-100 mg) for primary prevention among adults 40-70 years of age who are at higher ASCVD risk but not at increased risk of bleeding [16,63]. The recently published MESA trial data may help to clarify for whom the risk/benefit equation is more favourable in terms of disease prevention [46].…”

Statins and coronary artery calcium: What's the score?

“…Is his risk of future ASCVD truly optimized? In addition to lifestyle modification and initiation of a baby aspirin [15], one could argue that his LDL-C is not adequately controlled, given the evidence that individuals with CAC>300 AU exhibit ASCVD risk that approaches secondary prevention event rates [16]. While this thought process may make intuitive sense, there is currently no convincing evidence that setting specific LDL-C thresholds based on the extent of CAC improves outcomes.…”